Reprinted from: Issues in new crops and new uses. 2007. J. Janick and A. Whipkey (eds.). ASHS Press, Alexandria, VA. Quality Attributes of Ginger and Cinnamon Essential Oils from Madagascar Adolfina Koroch*, Lalasoa Ranarivelo, Olivier Behra, H. Rodolfo Juliani, and James E. Simon Over 28,200 tonnes (t) of essential oils are produced worldwide every year at an estimated value of $18 billion, of which China contributes about 16,600 t. African countries collectively contribute less than 1% of global production. One of the major factors limiting increased trade and market penetration of African essen- tial oils has been the lack of quality standards, inability to consistently produce the critical mass of essential oil quantities, high shipping costs, lack of familiarity with market requirements, and the challenge of meeting product specifications of the international marketplace. The natural products sector of Madagascar is dependent on international trade for its commercial success. Ginger (Zingiber officinale Roscoe, Zingiberaceae) and cinnamon (Cinnamomum zeylanicum Garc. ex Blume, Lauraceae) are among the most important essential oils from Madagascar and are used by the food and fragrance industries. This study sought to evaluate the quality of these Malagasy essential oils and compare them with commercial available products and standards from the US (Food Chemical Codex 1996) and inter- national organizations (ISO), to determine their market competitiveness. MATERIALS AND METHODS Essential oils extracted from fresh ginger rhizomes (Z. officinale) and cinnamon barks (C. zelyanicum) from Madagascar were analyzed. Organoleptic (color, aroma), physicochemical (refractive index, density, optical rotation, ethanol solubility) and chemical composition (Juliani et al. 2004) profiles were evaluated. A cluster analysis was performed to find associations between the different essential oils of ginger. The distances based on similarity (or dissimilarity) were illustrated as a Similarity Index which was used as a crite- ria for grouping or separating essential oils. The cluster analysis of the oils was performed using the program NTSYSpc (ver. 2.02, Applied Biostatistics Inc.). ReSULTS AND DISCUSSION Ginger Rhizomes of ginger (Zingiber officinale) are one of the most important and oldest spices (Fig. 1). The commercial ginger essential oil was characterized by warm, spicy, and woody notes, with slight lemony notes. The oils were pale yellow, low viscosity liquids, with refractive indices of 1.4884 to 1.4918, the densities of 0.883 to 0.877, and optical rotations of –33.9 to –39 (Table 1). These essential oils were dominated by α-zingiberene with low AR-cucurmene content and trace amounts of neral and geranial (Table 2). Two samples of Malagasy ginger oils had a dif- ferent aroma from the commercial oils. While the commercial oil could be characterized as imparting light lemony notes, the Madagascan ginger oil sample was characterized by a distinctly stronger and intense lemon character with rose/floral notes. Sample 1 ex- hibited properties including aroma, physicochemical properties and organoleptic characteristics that were distinctly different from sample 2. Fig. 1. Commercial ginger rhizomes. *We thank Chemonics International for providing both the funding and logistical support under their respective LDI and BAMEX projects in support of Madagascar natural products and the respective Malagasy essential oil producers. We also recognize and thank the USAID for providing the funding to Chemonics to conduct this work. The strong support and partnership provided by Jean Robert Estime, Chemonics Int., Antananarivo, Madagascar is greatly appreciated. 338 Botanicals and Medicinals A cluster analysis, performed to evaluate the chemical diversity of the essential oils, showed that Malagasy sample 1 did not belong to the typical commercial cluster (Fig. 2) as this oil contained high levels of camphene and AR-cucurmene and lower amounts of α-zingiberene (Table 2). Malagasy sample 2 showed lower levels of camphene and higher amounts of citral (geranial + neral), and α-zingiberene. Geranyl acetate (8%) of sample 2, an uncommon component in ginger oil, appeared to be responsible for the pleasant floral notes. Citral pro- vided the lemony notes. For comparison purposes, we included a sample form Ghana, which was similar to the Malagasy sample, though lacking geranyl acetate. The moisture content of the ginger at the time of distillation appeared to be related to the intensity of the lemony notes in the distilled oil. The fresher ginger produced higher lemony notes and aroma in the distilled essential oil. Cinnamon Essential oils extracted from commercial cinnamon barks (Fig. 3) were yellow, with warm-spicy notes char- acterized simply as “cinnamon notes” (Table 3). The refractive index (1.5817–1.5909) and density (1.019–1.026) of the commercial samples were closer to pure cinnamic aldehyde, reflecting the higher levels of cinnamic aldehyde (Table 4). Essential oil of Cinnamomum cassia was included for comparison purposes. The oils were Table 1. Appearance profile and physicochemical properties of ginger essential oils from different origins. Organoleptic profile Physicochemical properties Refractive Optical Origin Aroma Color index Density rotation (°) Malagasy 1 Less characteristic Yellow 1.4927 0.936 11.4 Malagasy 2 Characteristic of ginger, Pale yellow -- -- -- but with floral character Commercial 1 Characteristic of ginger Pale yellow 1.4884 0.8803 –33.9 Commercial 2 Characteristic of ginger Yellow-orange 1.4918 0.883 –39.3 Commercial 3 Characteristic of ginger Pale yellow 1.4894 0.877 –39.3 Guenther (1985) Characteristic of ginger Green to yellow 1.489–1.494 0.877–0.886 –26 to –50 FCCz Aromatic odor character- Yellow to pale 1.488–1.494 0.870–0.882 –28 to –47 istic of ginger yellow zFood Chemical Codex standards. Table 2. Chemical composition of ginger essential oils from different origins. Composition (rel. % of total EO) Madagascar Commercial Component 1 2 1 2 3 Ghana α-pinene 7.4 0.1 3.1 1.7 2.6 Camphene 22.8 1.0 10.4 5.7 8.1 0.2 β-phellandrene 8.2 0.9 9.1 5.4 7.3 0.4 1,8-cineole 8.7 2.0 4.1 2.2 3.2 0.9 Neral 2.4 6.4 0.1 0 11.2 Geranial 4.2 14.6 0.2 0.1 17.8 Geranyl acetate 8.3 AR-curcumene 15.3 7.7 8.8 8.2 9.1 4.5 α-zingiberene 5.2 22.9 36.2 42.2 39.7 18.1 β-bisabolene 7.4 8.5 10.1 11.5 11.3 6.4 β-sesquiphellandrene 6.3 6.5 9.6 13.5 10.9 6.8 Total analyzed 94.1 90.6 96.4 96.6 96.0 80.7 339 Issues in New Crops and New Uses dark orange, with refractive index (1.6119) and density (1.058) closest to pure cinnamic aldehyde, due to the highest amount (92%) of this component (Table 4). The optical rotation of the commercial essential oils were also similar ranging from –0.3 to –0.83 (Table 3). Madagascar essential oil was pale yellow, with weaker spicy or “cinnamon” notes. It exhibited lower re- fractive indexes and density, showing that this oil contained low levels of cinnamic aldehyde (29%), with higher amounts of monoterpene hydrocarbons, of which β-phellandrene was the main component (Table 4). This essential oil was insoluble in ethanol 70%, supporting the fact that the oil was richer in non-polar components, such as monoterpene hydrocarbons (Table 3). Although, the Malagasy essential oils showed different properties when compared with commercially avail- able oils, they received positive feedback from the private sector, and are now entering international markets for niche applications. The “lemon ginger” essential oils are thus now beginning to contribute to economic development in Madagascar though they will likely find their niche as a specialty item. We suggest such a new oil be accompanied with a specific international product specification sheet highlighting the high amounts of citral (geranial + neral), α-zingiberene and geranyl acetate as well as all other physicochemical attributes which illustrate the oils uniqueness from traditional ginger oil.. We also suggest that such an oil can be introduced into the market with a unique name so that it will not be confused with the essential oil of ginger now produced in several other countries. Despite the lower amount of cinnamic aldehyde, the organoleptic profile was desirable for some buyers seeking a milder less intense cinnamon, demonstrating that it is not always important to have high amounts of the main component as long as the essential oil has the desired or complex aroma profile of interest to specialized market niches. Yet there is a significant challenge in marketing such a cinnamon when the cinnamic aldehyde content does not meet the minimum levels set forth for this product in the ISO specifications. Cinnamomum cassia oil included in this study, had the highest levels of cinnamic aldehyde but also produced a hot, burning sensation. Ghana Madagascar 2 Commercial 1 Commercial 2 Commercial 3 Madagascar 1 0.7 1 1.4 1.7 2 Similarity Index Fig. 2. Cluster analysis of the ginger essential oils. Fig. 3. Commercial cinnamon barks. 340 Botanicals and Medicinals Table 3. Appearance profile and physicochemical properties of cinnamon bark oil from Madagascar with cin- namon bark oils (Cinnamomum zeylanicum) and cassia (Cinnamomum cassia) in the US Market. Appearance profile Physicochemical properties Ethanol Refractive Optical solubility Origin Aroma Color index Density rotation (ml EtOH) Malagasy Mildly sweet, weak Pale 1.5301 0.949 –3.9 Not and less rich yellow solublez aroma Commercial 1 Sweet, characteris- Yellow 1.5817 1.019 –0.3 1.7 tic of cinnamon, strong, rich and pleasant aroma Commercial 2 Sweet, characteris- Yellow 1.5909 1.026 –0.83 1.7 tic of cinnamon, strong, rich and pleasant aroma FCCy Odor of cinnamon Yellow 1.573–1.591 1.010–1.03 2 to 0 3.0 Cassia Cinnamon like, Dark 1.6119 1.058 –0.83 1.4 commercial 3 burning sensation orange z1 mL of oil in 1 mL of EtOH (70%) yFood Chemical Codex standards.